OSE Seminars
Spectroradiometric Monitoring for Real-Time Biomass Assessment and Early Detection of Pond Crash Conditions
Presented by Dr. J. Timlin, Bioenergy & Defense Technologies group, Sandia National Laboratories
Outdoor algal cultivation is accompanied by high environmental and temporal variability. Decisions concerning fertilizing, harvesting, and weed control need to be made within hours, and mistakes can result in total culture loss. Current technologies for assessing algal growth and productivity such as ash free dry weight, microscopy, and molecular measurements including qPCR and 16S/18S amplicon sequencing require physical sampling of ponds and subsequent offline analysis. These provide reliable measurements of biomass and culture composition, but have limited temporal resolution. To address the need for higher temporal resolution, we have been developing a stand-off, optical method, based on spectroradiometeric monitoring to enable real-time assessment of biomass, early detection of algal stress and the presence of invaders without the need for sampling the pond. The method takes advantage of the wavelength-specific interaction of the material within the algal pond with the sunlight to determine optical parameters corresponding to the biomass and pigments within the algae as well as several parameters indicative of culture invasion by predators and pathogens.
I will present examples highlighting the capability for early warning of invader presence via spectroradiometric monitoring from the current system, deployed long term at the Arizona Center for Algae Technology and Innovation (AzCATI) on six 4.3-m2 mini-raceway ponds as part of the Algae Testbed Public Private Partnership (ATP3). In this arrangement, pond reflectance spectra spanning from the visible into the near-infrared are acquired every 5 minutes with a multi-channel, fiber-coupled spectroradiometer. The spectra are interpreted via numerical inversion of a reflectance model, in which the above-water reflectance is expressed in terms of the absorption and backscatter coefficients of the cultured species, with additional terms accounting for the pigment fluorescence features and for the water-surface reflection of sunlight and skylight. Future applications of the methodology to large-area monitoring of algae and plants will be discussed.
11:00 am, Thursday, May 4, 2017
PAIS-2540, PAIS
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